ref: 20dc40d19bc63ff5d3a88248ce9864be5b2284c4
dir: /sys/src/cmd/spin/README/
the latest version of spin is always available via: http://spinroot.com/spin/whatispin.html to make the sources compile with the mkfile on Plan 9 the following changes were made: omitted memory.h from spin.h changed /lib/cpp to /bin/cpp in main.c simplified non_fatal() in main.c to remove use of yychar